According to the Ministry of Agriculture and Rural Development, this area accounts for 30 per cent of the total area under oyster farming.

Total losses are estimated at 30 tonnes of oysters worth nearly VND648 million (US$30,000).

The Cuu Long (Mekong) Delta provinces of Tien Giang, Ben Tre and Bac Lieu have been the hardest hit localities.

Local authorities have said that the oysters have died because of inclement weather, high salinity content in water, water pollution, and infections caused by parasites, fungus and bacteria.

Improper farming techniques, the lack of natural food in the dry season plus high temperatures have also been factors, they said.

However, speaking at a meeting on developing oyster farming held last month, Agriculture Minister Cao Duc Phat said the main reason for the oyster deaths has not yet been identified.

He ordered the Directorate of Fisheries to set up standard criteria for the oyster breeding process and submit them to the ministry for approval.

He also ordered relevant agencies and sectors to instruct farmers on restoring oyster farms to health and opening new farms. The quarantine system for oyster seeds needed to be strengthened, he said.

In early June, the agriculture ministry invested VND600 million in three-month to find ways to preventing oyster diseases.

In Viet Nam, oyster farming has been receiving increasing attention, especially in coastal areas, as it requires low investment capital and earns high profits.

Last year, the total area under oyster farming reached more than 15,000ha with an output of 85,000 tonnes. The country exported nearly 19,000 tonnes of oyster worth more than $40 million last year, according to the agriculture ministry. — VNS